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Title: Crystal growth and annealing method and apparatus

Abstract

A method and apparatus for producing crystals that minimizes birefringence even at large crystal sizes, and is suitable for production of CaF.sub.2 crystals. The method of the present invention comprises annealing a crystal by maintaining a minimal temperature gradient in the crystal while slowly reducing the bulk temperature of the crystal. An apparatus according to the present invention includes a thermal control system added to a crystal growth and annealing apparatus, wherein the thermal control system allows a temperature gradient during crystal growth but minimizes the temperature gradient during crystal annealing. An embodiment of the present invention comprises a secondary heater incorporated into a conventional crystal growth and annealing apparatus. The secondary heater supplies heat to minimize the temperature gradients in the crystal during the annealing process. The secondary heater can mount near the bottom of the crucible to effectively maintain appropriate temperature gradients.

Inventors:
 [1];  [2]
  1. (Albuquerque, NM)
  2. (North Brookfield, MA)
Publication Date:
Research Org.:
SANDIA CORP
OSTI Identifier:
874085
Patent Number(s):
US 6309461
Assignee:
Sandia Corporation (Albuquerque, NM); Corning, Incorporated (Corning, NY) SNL
DOE Contract Number:  
AC04-94AL85000
Resource Type:
Patent
Country of Publication:
United States
Language:
English
Subject:
crystal; growth; annealing; method; apparatus; producing; crystals; minimizes; birefringence; sizes; production; cafsub2; maintaining; minimal; temperature; gradient; slowly; reducing; bulk; thermal; control; added; allows; embodiment; secondary; heater; incorporated; conventional; supplies; heat; minimize; gradients; process; mount; near; bottom; crucible; effectively; maintain; appropriate; crystal growth; /117/

Citation Formats

Gianoulakis, Steven E., and Sparrow, Robert. Crystal growth and annealing method and apparatus. United States: N. p., 2001. Web.
Gianoulakis, Steven E., & Sparrow, Robert. Crystal growth and annealing method and apparatus. United States.
Gianoulakis, Steven E., and Sparrow, Robert. Mon . "Crystal growth and annealing method and apparatus". United States. https://www.osti.gov/servlets/purl/874085.
@article{osti_874085,
title = {Crystal growth and annealing method and apparatus},
author = {Gianoulakis, Steven E. and Sparrow, Robert},
abstractNote = {A method and apparatus for producing crystals that minimizes birefringence even at large crystal sizes, and is suitable for production of CaF.sub.2 crystals. The method of the present invention comprises annealing a crystal by maintaining a minimal temperature gradient in the crystal while slowly reducing the bulk temperature of the crystal. An apparatus according to the present invention includes a thermal control system added to a crystal growth and annealing apparatus, wherein the thermal control system allows a temperature gradient during crystal growth but minimizes the temperature gradient during crystal annealing. An embodiment of the present invention comprises a secondary heater incorporated into a conventional crystal growth and annealing apparatus. The secondary heater supplies heat to minimize the temperature gradients in the crystal during the annealing process. The secondary heater can mount near the bottom of the crucible to effectively maintain appropriate temperature gradients.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = {2001},
month = {1}
}

Patent:

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